Dentures are removable appliances that serve as a replacement for missing teeth and neighboring structures in the oral cavity. Denture fixative compositions are widely used to hold dentures in place, both while the user's mouth is at rest and particularly during mastication. Such denture fixative compositions should also perform their intended function without causing irritation to the mucosal denture surfaces. Ideal denture fixative compositions make the users of dentures confident that their dentures will remain fixed in place while functioning as intended. This is sometimes difficult to achieve particularly where dentures are not fitted perfectly or where the denture fit deteriorates over time due to denture wear or changes in the mucosal denture surfaces.
Denture fixatives come in many forms including pastes, liquids, powders and aerosols. Denture fixatives may also be supplied as liners or adhesive-like strips. In all cases, it is important that good tack is achieved as soon as the dentures are properly positioned in the mouth. It is also important that the fixatives be capable of being readily spread and distributed across the denture-mucosal interface to produce sufficient adhesion to resist the stresses encountered upon mastication. Finally, the fixatives must perform well under the environmental changes typically encountered in the user's mouth such as the temperature changes experienced in drinking very hot or very cold beverages like tea, coffee or cold iced drinks or eating very hot or very cold foods.
Over the years, there have been numerous improvements in denture fixative compositions. Both synthetic and natural polymers and gums have been used alone or in combination with denture fixative compositions and have been combined with various adhesives and other materials in order to achieve such improvements. For example, denture fixative compositions using alkyl vinyl ether-maleic copolymers and salts and derivatives thereof are known to provide good adhesion. U.S. Pat. No. 3,003,988 to D. P. Germann et al., issued Oct. 10, 1961, describes certain synthetic water-sensitized water-insoluble polymeric materials comprising synthetic, hydrophilic, colloidal materials in the form of mixed partial salts of lower alkyl vinyl ether-maleic anhydride-type copolymers, where the mixed partial salts and esters contain both divalent calcium and monovalent alkali cations. U.S. Pat. No. 4,373,036 to Tiang-Shing Chang et al., issued Feb. 8, 1983, relates to improved denture fixative compositions containing a dentally acceptable excipient and a fixative mixture comprising hydroxypropyl cellulose and at least one partially neutralized alkyl vinyl ether-maleic acid or anhydride copolymer, optionally partly crosslinked, a partially neutralized, optionally partly crosslinked polyacrylic acid, or a precursor combination of copolymer or polyacrylic acid, neutralizing agents, and optionally crosslinked agents or polyethylene oxide. U.S. Pat. No. 5,006,571 to Lori D. Kumar et al, issued Apr. 9, 1991, describes improved denture adhesive base compositions comprising a substantially anhydrous mixture of a mixed Na/Ca salts of methyl vinyl ether-maleic acid, sodium carboxymethyl cellulose and a trivalent cation.
It is therefore an important object of this invention to provide new and improved denture fixative compositions that resist the stresses at the denture-mucosal interface encountered upon mastication.
It is a further object of the present invention to provide denture fixative compositions that work well immediately after application and retain their fixative properties for prolonged periods of time.
Yet another object of the present invention is to provide denture fixative compositions that perform well in spite of the extreme environmental changes typically encountered in the user's mouth.
Still another object of the present invention is to provide denture fixative compositions that do not cause oral mucosal irritation and further may be used to protect select areas of the gums or other oral surfaces.
These and other objects of the invention will become apparent to those skilled in the art from the following detailed description of the invention.